Yea, I'd say that's pretty annoying that Marketo comes up as the company getting your info -- although, I get it. Marketo is getting access, not you guys. I'd say that for someone who doesn't know what Wet Republic is, I got a little nervous it would be totally NSFW when I saw the image related to posting on Facebook. I had to do a quick Google search to learn more!
We had a similar initial reaction. You will need to complete a 4-page "Branding the “Allow” Screen and Share Experience" document and then work with Marketo professional services (for a fee, of course) to properly brand this for your company.
A while back, I posted this discussion to the community, hoping to get some more insight on where Marketo is taking its social capabilities: Re: Anyone using the Marketo "Social Boost & Promotion" add-on? Is it worth it for B2B marketers?